Study of the Reduction of Particulate Emission from a Direct Diesel Engine: (2nd Report, Oxygen-Enriched Charging and Characteristics of Particulates)

The effect of oxygen-enriched charging (OEC) of particulate emissions was investigated by using a direct injection engine. The total mass of particulate emission was measured, using a dilution tunnel sampling system, and the mass fraction of SOF and dry soot were measured. The Shape, structure and the distributions of particulates obtained with a freezing sampling method just behind the exhaust valve were measured. Both SOF and dry soot were reduced by OEC under broad operating conditions. At high load condition, dry soot was remarkably suppressed by OEC, but OEC had little effect on particulate size distribution.